KR20110119684A - Inorganic fiber structure and process for producing same - Google Patents

Abstract

An inorganic fiber structure composed of inorganic nanofibers having an average fiber diameter of 3 μm or less, and an inorganic fiber structure having a porosity of 90% or more, in which the whole including the inside is bonded with an inorganic adhesive. Further, (i) spinning a inorganic fiber by an electrospinning method from a spinning inorganic sol solution containing a compound mainly composed of an inorganic component, and (ii) irradiating ions having a polarity opposite to that of the inorganic fiber, To form an inorganic fiber aggregate, and (iii) to provide the whole inorganic material including the inside of the inorganic fiber aggregate to a bonding inorganic sol solution containing a compound mainly composed of inorganic components, and to provide a surplus of inorganic sol for adhesion. Disclosed is a method for producing an inorganic fiber structure including a step of removing the solution by aeration and forming an inorganic fiber structure bonded with an inorganic adhesive in the whole including the inside.

Description

Inorganic fiber structure and its manufacturing method {INORGANIC FIBER STRUCTURE AND PROCESS FOR PRODUCING SAME}

The present invention relates to an inorganic fiber structure (particularly an inorganic fiber structure having functionality) and a method for producing the same. The inorganic fiber structure of the present invention can be used, for example, in cell culture carriers, scaffolds, antibacterial materials and the like.

Conventionally, according to the electrospinning method, fibers having even fiber diameters form a three-dimensional network structure, whereby a nonwoven fabric having a uniform hole diameter can be produced.

This electrospinning method is a method of spinning by supplying the spinning stock solution to the spinning space, applying the electric field to the supplied spinning stock solution, drawing it, and integrating it on the counter electrode. Thus, the fibers drawn and spun by the action of the electric field are integrated into the force of the electric field directly on the counter electrode, thereby becoming a paper nonwoven fabric. However, when it is used for a heat insulating material, a filtration use, etc., it is preferable that it is a bulky nonwoven fabric.

Therefore, the applicant of the present application includes the steps of applying a charge to a polymer solution to be spun, supplying the charged polymer solution to a spinning space and flying by an electrostatic force, and the fibers formed by the supplying fiber. The manufacturing method of the bulky nonwoven fabric (= neutral spinning method, patent document 1, 2) containing the step of irradiating the ion of opposite polarity, and the step of collect | recovering the spun fiber was proposed.

This bulky nonwoven fabric is a low density cotton nonwoven fabric with no fibers bonded to each other or very weakly bonded to each other. Therefore, the bulky nonwoven fabric can be applied to applications that do not require retention or strength. However, in the applications requiring shape retention and strength, such as liquid filtration, the form of the nonwoven fabric could not be maintained and was not suitable for practical use.

Therefore, the following method can be considered as a method for providing the shape retention and strength of the neutralized spun inorganic fiber nonwoven fabric, for example.

(1) A method of producing an inorganic fiber nonwoven fabric by impregnating an inorganic fiber

(2) Method of spraying and drying binder on inorganic fiber nonwoven fabric

(3) After the inorganic fiber nonwoven fabric is immersed in a binder bath, it is passed through a two roll press machine (an apparatus which adds a pressure), the excess binder is removed, and the method of drying after that is carried out.

However, in the method of (1), papermaking of nanofibers by the electrospinning method is very difficult. In the method of (2), it is difficult to uniformly apply the binder to the entire inorganic fiber nonwoven fabric (particularly up to the inside of the nonwoven fabric), and it is inferior in strength. In the method of (3), the void of the inorganic fiber nonwoven fabric is crushed, and bulkiness cannot be maintained, and the void ratio is lowered.

By the way, the fiber structure including such an inorganic fiber nonwoven fabric can be applied to a culture carrier. In order to cultivate cells in close proximity to the environment in vivo, there is a technique of inducing tissue formation by three-dimensional culturing of cells. As this culture carrier, films, particles, hollow fibers, fiber aggregates, foams and the like are known.

However, these culture carriers have insufficient surface area for scaffolding of the cells required for three-dimensional culture, so that it is difficult to cultivate high density of cells or have a tissue forming ability similar to that of the living environment. Many times they are not doing.

As a culture carrier capable of solving the problems of the conventional culture carrier and allowing three-dimensional culture, a scaffold containing nanofibers produced by the electro-spinning method has been proposed ( Patent Document 3). In a specific Example, the nanofiber which consists of a silica and PVA is used.

However, even a scaffold containing such nanofibers had low cell proliferation ability, making it difficult to carry out high-density culture, and poorly expressing cell functions. Furthermore, it was difficult to control the fiber density and thickness, and because the cell masses were formed unevenly, it was difficult to observe the culture state.

Moreover, in order to provide a function to a fiber structure, provision of a metal ion containing compound is performed. For example, it is involved in a wide range of biological reactions such as cell division, proliferation and differentiation, blood coagulation, muscle contraction, excitability of nerve sensory cells, phagocytosis, antigen recognition, immune reactions such as antibody secretion, and various hormone secretions. In addition, it forms hydroxyapatite crystals with phosphorus and deposits it on the matrix structure of bones and teeth to give strength, and calcium and extracellular fluids that act to maintain the osmotic pressure of sodium and oxygen. Iron, an essential part of the electron transporter (cytochrome C) in transport and energy metabolism, magnesium as a major inorganic component of bone and teeth, maintenance of nerve excitability, muscle contraction, and osmotic pressure in cells Cell culture apparatus that can improve cellular function by imparting metals such as potassium or copper, iodine, selenium, chromium, zinc and molybdenum to the fiber structure It can be used as ash or as a fiber structure having antibacterial performance.

For example, Patent Document 3 discloses "a scaffold containing nanofibers modified by surface adhesion factors (particularly calcium phosphate) produced by the electro-spinning method" (claims 1, 8, 9). It has been proposed. Specifically, silica nanofibers synthesized by the sol-gel method are suitable, hydrophilic or hydrophobic according to the firing temperature of the silica nanofibers, and cell adhesion can be manipulated. Silica nanofibers are incubated in artificial fluid By doing so, the lime can be precipitated on the surface of the nanofibers, and those useful as cell carriers for artificial bone, and the like are disclosed (paragraphs 0015, 0018, 0025, etc.).

However, scaffolds containing these nanofibers were of low cellular function.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2004-238749 [Patent Document 2] Japanese Unexamined Patent Publication No. 2005-264374 [Patent Document 3] Japanese Unexamined Patent Publication No. 2007-319074

The problem of the present invention is to solve these problems of the prior art, and to use a bulky inorganic fiber structure which can be used for applications requiring shape retention and strength, and excellent in the above-mentioned performance, thereby having high cell proliferation ability and high density culture. In addition, the inorganic fiber structure having excellent functionality, such as easy to express cell function, control of fiber density and thickness, easy to observe the culture state, high cellular function, excellent antibacterial properties, And a method for producing the same.

The present invention relates to (1) an inorganic fiber structure made of inorganic nanofibers having an average fiber diameter of 3 μm or less, the inorganic fiber structure having a porosity of 90% or more, including the whole, bonded with an inorganic adhesive;

(2) the inorganic fiber structure of (1), wherein the tensile breaking strength is 0.2 MPa or more;

(3) the inorganic fiber structure according to (1) or (2), wherein the amount of hydroxyl groups per fiber weight of the fiber is 50 µmol / g or more;

(4) The inorganic fiber aggregate produced by the electrostatic spinning method including the step of irradiating and integrating ions of opposite polarity to the inorganic fibers and integrating the inorganic fiber aggregates, including the inside, as an inorganic adhesive Bonded inorganic fiber structures of (1) to (3);

(5) the inorganic fiber structure of (1) to (4), in which no film is formed between the inorganic fiber;

(6) an inorganic fiber structure having functionality wherein a metal ion-containing compound is imparted to the inorganic fiber structure of (1) to (5);

(7) the inorganic fiber structure of (1) to (6), which is used as a culture carrier;

(8) (i) spinning a inorganic fiber from the spinning inorganic sol solution containing a compound mainly composed of an inorganic component by electrostatic spinning;

(Ii) irradiating and integrating ions of opposite polarity to the inorganic fibers to form an inorganic fiber aggregate, and

(Iii) Applying the inorganic sol solution for the adhesive containing the compound mainly composed of the inorganic component to the whole including the inside of the inorganic fiber aggregate, and removing the excess adhesive inorganic sol solution by aeration. In the whole including the inside, The manufacturing method of an inorganic fiber structure including the process of forming the inorganic fiber structure bonded by the inorganic adhesive;

(9) The method of manufacturing the inorganic fiber structure of (8) which is heat-processed after forming an inorganic fiber aggregate in the process of forming an inorganic fiber aggregate (ii);

(10) The method for producing the inorganic fiber structure of (9), wherein the heat treatment temperature is 500 ° C. or less;

(11) (iii) A method of producing an inorganic fiber structure according to (8) to (10), wherein the step of forming an inorganic fiber structure includes heat treatment after removing the excess adhesive inorganic sol solution by aeration;

(12) The manufacturing method of the inorganic fiber structure of (11) whose heat processing temperature is 500 degrees C or less;

(13) The method for producing the inorganic fiber structure of (8) to (12), wherein the spinning inorganic sol solution and / or the bonding inorganic sol solution contains a metal ion-containing compound;

(14) (iii) After performing the process of forming an inorganic fiber structure, it is related with the manufacturing method of the inorganic fiber structure of (8)-(13) which gives a metal ion containing compound containing solution to the said inorganic fiber structure.

The inorganic fiber structure of the present invention according to the above (1) is excellent in shape retention and has sufficient strength because the whole including the inside is bonded with an inorganic adhesive. Especially in a liquid, it is excellent in shape retention and has sufficient strength. Moreover, since the porosity of an inorganic fiber structure is 90% or more, bulky things, such as a use of a heat insulating material, a filtration use, a culture carrier use, such as a cell, a scaffold use, and an antibacterial material use, are applicable.

According to a preferred embodiment of the present invention of (2), the tensile strength at break is 0.2 MPa or more, so the shape retention is excellent and the strength is sufficient.

According to another preferred embodiment of the present invention of (3), since the amount of hydroxyl groups per fiber unit weight is 50 µmol / g or more, apatite or the like can be deposited on the fiber surface, thereby imparting a function to the inorganic fiber structure. can do.

According to still another preferred embodiment of the present invention of (4), the fiber spun by the electrospinning method is used, and because the fiber diameter is thin, the surface area is wide. Furthermore, since the hole diameter distribution is uniform, a uniform space exists inside the inorganic fiber structure. As a result, the function can be sufficiently exhibited. For example, when used as a culture carrier, since the surface area serving as a cell scaffold is large, three-dimensional culture in a uniform space having a large surface area is possible. In addition, the adhesion efficiency between the cells and the fibers serving as the scaffolds of the cells is improved, and further, the supply efficiency of nutrients and oxygen, which are indispensable to the cells, is improved. Can be.

In addition, inorganic fibers are irradiated with ions of opposite polarity to inorganic fibers to form inorganic fiber aggregates, that is, as a result of high porosity (bulky) of 90% or more derived from the neutralizing spinning method, the inorganic fibers are low. The inside of the structure can be used effectively. For example, when used as a culture substrate, since the fiber density is low, the cell is easily spread to the inside of the culture carrier. Further, since the inorganic fibers are irradiated with ions of opposite polarity and accumulated to form an inorganic fiber aggregate, the fiber density and thickness can be controlled until they become bulky and observable. In addition, since ions of opposite polarity to the fiber are irradiated and accumulated, a high porosity of 90% or more is achieved.

Furthermore, because it is an inorganic fiber aggregate, the thickness does not deform when giving an inorganic adhesive. As a result, control of fiber density and thickness is possible. Therefore, when used as a culture substrate, it is easy to observe the culture state.

Furthermore, since it is adhere | attached with an inorganic adhesive agent, it can maintain a form under various use conditions, such as in a solution, and can therefore utilize the inside of an inorganic fiber structure effectively. In the case of the culture substrate, the cells can be cultured in three dimensions, and the cells are cultured in a state close to the tissue environment, whereby cell functions can be easily expressed.

Furthermore, since the inorganic fiber structure is adhered with the inorganic adhesive in the whole including the inside, it is possible to maintain the porosity of 90% or more. For example, when it is used as a culture carrier, it is possible to improve the supply efficiency of nutrients and oxygen, which are indispensable to the cells, and because there are many scaffolds required for cell culture, high density culture can be performed.

According to still another preferred embodiment of the present invention of (5), the inorganic fiber structure has a porosity of 90% or more because the inorganic fiber structure is adhered with an inorganic adhesive without forming a film between the inorganic fibers in the whole including the inside. It is possible to keep. For example, when used as a culture carrier, it is possible to improve the supply efficiency of nutrients, oxygen and the like which are indispensable to the cells, and since there are many scaffolds required for cell culture, high density culture can be achieved.

According to still another preferred embodiment of the present invention described in (6), since the metal ion-containing compound is provided and contained, the cell function is high, and the antibacterial property is excellent.

According to still another preferred embodiment of the present invention described in (7) above, when the inorganic fiber structure of the present invention is used as a culture carrier, the average fiber diameter is thin to 3 µm or less, so that the surface area is wide. As a result, the adhesion efficiency between the cells and the fibers serving as the scaffolds of the cells is improved, and further, the supply efficiency of nutrients and oxygen, which are indispensable to the cells, is improved, so that the cell proliferation ability is excellent and high density culture can be performed. .

Moreover, since it is adhere | attached with an inorganic adhesive agent, the form can be maintained also in a culture liquid. As a result, since the bulky structure of the inorganic fiber structure can be maintained, it can be cultured in three dimensions, and since cells are cultured in a state close to the tissue environment, it is easy to express cell function.

According to the manufacturing method of this invention of said (8), the inorganic fiber structure of this invention can be manufactured. In particular, since the excess adhesive inorganic sol solution is removed by aeration, the bulky state bonded to the inorganic adhesive is maintained without forming a film between the inorganic fibers in the whole including the inside. In addition, an inorganic fiber structure having excellent shape retention and strength can be produced.

According to a preferred embodiment of the present invention of (9), in the step of forming the inorganic fiber aggregate, the heat treatment is performed after the inorganic fiber aggregate is formed, so that the structure and the heat resistance of the inorganic fiber structure are stable.

According to another preferred embodiment of the present invention of (10), since the heat treatment temperature is 500 ° C or less, the hydrophilicity of the inorganic fiber structure can be improved. Moreover, when using as a culture base material, it is easy to culture a cell in the form of a spheroid.

According to still another preferred embodiment of the present invention described in (11), in the step of forming the inorganic fiber structure, the inorganic adhesive sol solution is heat treated after removing the excess adhesive inorganic sol solution by aeration. The strength and heat resistance of the fiber structure are improved.

According to still another preferred embodiment of the present invention of (12), since the heat treatment temperature is 500 ° C or less, the hydrophilicity of the inorganic fiber structure can be improved. Moreover, when using as a culture base material, it is easy to culture a cell in the form of a spheroid.

According to still another preferred embodiment of the present invention described in (13), since the inorganic sol solution for spinning and / or the inorganic sol solution for adhesion contains a metal ion-containing compound, the cell contains a metal ion-containing compound, and the cell The inorganic fiber structure excellent in functionality, such as high function and excellent antibacterial property, can be manufactured.

According to still another preferred embodiment of the present invention described in (14), since the metal ion-containing compound-containing solution is imparted to the inorganic fiber structure, the metal ion-containing compound is contained, the cell function is high, and the antibacterial property is excellent. The inorganic fiber structure excellent in functionality can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which showed typically embodiment of the electrostatic spinning apparatus which can perform the spinning process (1) and the integration process (2) in the manufacturing method of this invention.
2 is an explanatory view schematically showing an edge electrode dipped in a spinning inorganic sol solution.
FIG. 3 is an explanatory view schematically showing a wire electrode in a conveyor form dipped in a spinning inorganic sol solution. FIG.
FIG. 4A is a plan view schematically showing the structure of a surface discharge element, and (b) is a side view schematically showing the structure of a surface discharge element.
FIG. 5: is explanatory drawing which showed typically another embodiment of the electrostatic spinning apparatus which can perform the spinning process (1) and the integration process (2) in the manufacturing method of this invention.
FIG. 6: is explanatory drawing which showed typically another embodiment of the electrostatic spinning apparatus which can perform the spinning process (1) and the integration process (2) in the manufacturing method of this invention.
FIG. 7 is a SEM photograph showing the morphology of CHO-K1 cells cultured on culture carrier A of the present invention prepared in Example 10 for 14 days.
8 is a SEM photograph showing the morphology of CHO-K1 cells cultured on a comparative culture carrier c prepared in Comparative Example 10 for 14 days.
9 is a graph showing the cell adhesion rate of CHO-K1 cells on the culture carrier A of the present invention prepared in Example 10 and the comparative culture carriers a to c prepared in Comparative Examples 8 to 10.
FIG. 10 is a graph showing cell number change per dish of CHO-K1 cells up to 14 days of culture in each culture carrier shown in FIG. 9.
Figure 11 shows the change in the number of cells per unit dish of HepG2 cells up to 14 days of culture in the culture carrier A of the present invention prepared in Example 10, and the comparative culture carriers a to c prepared in Comparative Examples 8 to 10 This is the graph shown.
FIG. 12 is a graph showing the results of measuring ammonia removal ability (change in ammonia concentration per unit dish) in the medium brought by HepG2 cells up to 14 days of culture in each culture carrier shown in FIG. 11.
FIG. 13 is a graph showing the results of measuring albumin concentration change (per unit dish) of HepG2 cells up to 14 days of culture in each culture carrier shown in FIG. 11.
Fig. 14 is a graph showing the cell number trends of the inorganic fibrous structures of Examples 11 to 13, which are preferred embodiments of the present invention, and human osteosarcoma MG63 cells cultured for 21 days on each of the samples of Examples 14 to 15 of the present invention.
FIG. 15 shows the time course of enzymatic activity (unit: ABS / 10 ³ cells) per unit cell of alkaline phosphatase (ALP) secreted by human osteosarcoma MG63 cells in the culture shown in FIG. 14. This graph shows
FIG. 16 is a graph showing the value of the 14th day of culture with respect to the ALP enzyme activity shown in FIG. 15.
17 is a graph showing the relationship between the heat treatment temperature and the amount of hydroxyl groups.
18 is a SEM photograph showing the morphology of HepG2 cells cultured on the culture carrier of Reference Example 1 for 14 days.
19 is a SEM photograph showing the morphology of HepG2 cells cultured on the culture carrier of Reference Example 2 for 14 days.
20 is a SEM photograph showing the morphology of HepG2 cells cultured on the culture carrier of Reference Example 14 for 14 days.
21 is a SEM photograph showing the morphology of HepG2 cells cultured on the culture carrier of Reference Example 14 for 14 days.

EMBODIMENT OF THE INVENTION Hereinafter, according to an accompanying drawing, the manufacturing method of this invention is demonstrated, Furthermore, the inorganic fiber structure of this invention is demonstrated.

The manufacturing method of the present invention,

(1) A step (spinning step) of spinning an inorganic fiber by an electrospinning method from a spinning inorganic sol solution containing a compound mainly composed of an inorganic component,

(2) a step (integration step) of irradiating and integrating ions of opposite polarity to the inorganic fiber to form an inorganic fiber aggregate;

(3) To the whole including the inside of the said inorganic fiber aggregate, the adhesive inorganic sol solution containing the compound which mainly uses an inorganic component is provided, and the excess adhesive inorganic sol solution is removed by ventilation. In the whole including the inside, including the step of forming an inorganic fiber structure bonded with an inorganic adhesive (adhesive step), if desired,

(4) The method of providing a metal ion containing compound containing solution to the said inorganic fiber structure, and providing a functional property to an inorganic fiber structure (metal ion containing compound containing solution provision process) can further be included.

In the manufacturing method of this invention, the inorganic sol solution for spinning used in the spinning process (1), and / or adhesion instead of the said metal ion containing compound containing solution provision process (4), or in addition to the said process (4). A metal ion containing compound can be added to the adhesion | attachment inorganic sol solution used at a process (3).

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which showed typically one Embodiment of the electrostatic spinning apparatus which can implement the spinning process (1) and the integration process (2) in the manufacturing method of this invention.

In Fig. 1, the electrostatic spinning device 1 includes a spinning nozzle 2 for discharging an inorganic sol solution for spinning containing a compound mainly composed of an inorganic component, which is a raw material of fiber, and the spinning nozzle 2 The collecting member (for example, a net, a conveyor, etc.) 4 arrange | positioned in the fiber recovery container 3 which is a fiber recovery apparatus arrange | positioned below the front-end | tip of the side is provided. Moreover, it is arrange | positioned facing the spinning nozzle 2, and is the ion generating means which generate | occur | produces the ion of the opposite polarity to the fiber formed by discharge, and is provided with the counter electrode 5 which can electrically suck a fiber. A sol solution supply 6 for supplying an inorganic sol solution for spinning is connected to the spinning nozzle 2, and the first high voltage power supply 7 and the second high voltage are respectively connected to the spinning nozzle 2 and the counter electrode 5. The power source 8 is connected. In addition, the fiber recovery container 3 is provided with a suction machine 9 for sucking the fibers into the fiber recovery container 3.

As the spinning nozzle 2, a metal and nonmetallic pipe having an inner diameter of about 0.01 to 5 millimeters can be used. In addition, as shown in FIG. 2, the toothed gear 20 which rotates is immersed in the sol solution container 22 containing the inorganic sol solution 21 for spinning, and the toothed gear which faces the counter electrode 5 is rotated. The edge electrode which uses the front-end | tip part 20a of (20) as an electrode can be used. Similarly, as shown in FIG. 3, the wire 20b is rotated in the sol solution container 22 by the roller 23, and the wire 20b in the form of a conveyor with the spinning inorganic sol solution 21 is attached. It can also be used as an electrode. 3, the counter electrode (not shown) is arrange | positioned perpendicularly to the surface. Furthermore, various conventional electrostatic radiation electrodes can also be used.

As the counter electrode 5, a corona discharge needle (may be high voltage applied or grounded), a corona discharge wire (may be high voltage applied or grounded), an AC discharge element, or the like can be used. As the AC discharge element, a creepage discharge element as shown in FIG. 4 can be used. That is, in FIG. 4, the surface discharge element 25 provides the discharge electrode 27 and the organic electrode 28 with the dielectric substrate 26 (for example, an alumina film) interposed. Then, by applying a high voltage of alternating current between these electrodes, creeping discharge can be generated in the discharge electrode 27 portion to generate positive and negative ions.

In the spinning step (1), first, a step of forming a spinning inorganic sol solution containing a compound mainly composed of (1) an inorganic component is performed. As used herein, "mainly composed of inorganic components" means that the inorganic components occupy 50 mass% or more, more preferably 60 mass% or more, and more preferably 75 mass% or more.

This spinning inorganic sol solution hydrocondenses a solution (raw material solution) containing a compound containing an element constituting the inorganic fiber finally obtained by the production method of the present invention at a temperature of about 100 ° C. or less. Can be obtained. The solvent of the raw material solution is, for example, an organic solvent (for example, alcohol) or water.

The elements constituting this compound are not particularly limited, but, for example, lithium, beryllium, boron, carbon, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, potassium, calcium, scandium, titanium, vanadium, chromium and manganese , Iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, selenium, rubidium, strontium, yttrium, zirconium, niobium, molybdenum, cadmium, indium, tin, antimony, tellurium, cesium, barium, lanthanum, hafnium, Tantalum, tungsten, mercury, thallium, lead, bismuth, cerium, praseodymium, neodium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or ruthetium.

The above-mentioned compound is, for example, may be made of an oxide of the elements, _{specifically, SiO 2, Al 2 O 3} , B 2 O 3, TiO 2, ZrO 2, CeO 2, FeO, Fe 3 O 4 , Fe ₂ O ₃ , VO ₂ , V ₂ O ₅ , SnO ₂ , CdO, LiO ₂ , WO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , In ₂ O ₃ , GeO ₂ , PbTi ₄ O ₉ , LiNbO ₃ , BaTiO ₃ , PbZrO ₃ , KTaO ₃ , Li ₂ B ₄ O ₇ , NiFe ₂ O ₄ , SrTiO ₃ And the like. Said inorganic component may be comprised from the oxide of one component, and may be comprised from the oxide of two or more components. For example, it may be composed of two components, SiO ₂ -Al ₂ O ₃ .

The above-mentioned inorganic sol solution for spinning needs to have a viscosity at which spinning is possible in the step of forming a fiber to be described later. The viscosity is not particularly limited as long as it is a spinnable viscosity, but it is preferably 0.1 to 100 poise, more preferably 0.5 to 20 poise, particularly preferably 1 to 10 poise, most preferably 1 to 5 poise. This is because when the viscosity exceeds 100 poises, fine fiberization becomes difficult, and when the viscosity is less than 0.1 poises, the fiber shape tends to be impossible to obtain. In addition, when using a nozzle, when making the atmosphere in a nozzle tip part into the same solvent gas atmosphere as a raw material solution, even if it is an inorganic sol solution for spinning exceeding 100 poise, it may be able to spin.

The inorganic sol solution for spinning used in the spinning step (1) may contain an organic component in addition to the inorganic components as described above, and as the organic component, for example, an organic low molecule such as a silane coupling agent or a dye Organic high molecular compounds, such as a compound and polymethyl methacrylate, etc. are mentioned. More specifically, when the compound contained in the said raw material solution is a silane type compound, the compound in which the silane type compound organic modified by the methyl group or the epoxy group was polycondensed may be included.

The raw material solution is a solvent for stabilizing a compound contained in the raw material solution (for example, an organic solvent (for example, alcohols such as ethanol, dimethylformamide) or water), the compound contained in the raw material solution It may include water for hydrolysis and a catalyst (for example, hydrochloric acid, nitric acid, etc.) capable of smoothly proceeding the hydrolysis reaction. In addition, the raw material solution may be, for example, a compound capable of imparting various functions such as a chelating agent for stabilizing the compound, a silane coupling agent for stabilizing the compound, piezoelectricity, etc., improving adhesion, flexibility, hardness (brittleness ( It may contain an additive, such as an organic compound (for example, polymethyl methacrylate), or dye for adjustment. In addition, these additives can be added before hydrolysis, when hydrolyzing, or after hydrolysis.

In addition, the raw material solution may contain inorganic or organic fine particles. Examples of the inorganic fine particles include titanium oxide, manganese dioxide, copper oxide, silicon dioxide, activated carbon, and metal (for example, platinum). Examples of the organic fine particles include pigments and pigments. Moreover, the average particle diameter of microparticles | fine-particles is although it does not specifically limit, Preferably it is 0.001-1 micrometer, More preferably, it is 0.002-0.1 micrometer. By including such microparticles | fine-particles, optical function, porosity, a catalyst function, an adsorption function, an ion exchange function, etc. can be provided. Furthermore, the said raw material solution may contain the metal ion containing compound demonstrated in detail in the metal ion containing compound containing solution provision process (4), and may not contain it.

In the case of tetraethoxysilane, when the amount of water exceeds 4 times (molar ratio) of an alkoxide, it becomes difficult to obtain a normal sol solution, It is preferable that it is 4 times or less of an alkoxide.

If a base is used as a catalyst, it is difficult to obtain a normal sol solution, and therefore it is preferable not to use a base.

The reaction temperature may be equal to or less than the breaking point of the solvent used, but the lower one is moderately slower in reaction rate, making it easy to form an ordinary sol solution. Since reaction does not progress well even if it is excessively low, it is preferable that it is 10 degreeC or more.

The process (that is, spinning process (1) and integration process (2)) of forming an inorganic fiber assembly by the above-mentioned electrostatic spinning apparatus 1 is performed as follows. First, the inorganic sol solution for spinning which becomes the raw material of the fiber to be spun is supplied from the sol solution supply 6 to the spinning nozzle 2. Next, in the state where high voltage is applied between the spinning nozzle 2 and the counter electrode 5, the spinning inorganic sol solution is discharged from the tip of the spinning nozzle 2. Then, the charged liquid sol solution volatilizes, solidifies, and proceeds to the counter electrode 5 as a gel-type inorganic fiber (above, spinning step (1)). At this time, the ions 5a are irradiated toward the fiber from the counter electrode 5 arranged to face the spinning nozzle 2. This ion neutralizes the charging of the fiber, loses the emergency force due to the electrostatic force, and recovers the fiber from the fiber recovery container 3 by dropping along the gravity or by the breezy. Therefore, it is possible to obtain an inorganic fiber aggregate having a low density with a low density (above, the integration step (2)).

In addition, generation and irradiation of ions can be performed continuously or discontinuously. In addition, an electric field may be generated between the spinning nozzle 2 and the counter electrode 5, and a high voltage may be applied to only one side and the other side may be grounded. In addition, the spinning nozzle 2 may or may not be heated.

FIG. 5: is explanatory drawing which showed typically another embodiment of the electrostatic spinning apparatus which can perform the spinning process (1) and the integration process (2) in the manufacturing method of this invention.

In FIG. 5, the electrostatic spinning device 1A can generate ions in Embodiment 1 and can irradiate ionizing radiation instead of the counter electrode 5 capable of sucking fibers. The electrostatic radiation device 1 and the ionizing radiation source 10 and the net-type counter electrode 5 (connected to the third high voltage power source 11) capable of attracting fibers are used. Since the configuration is the same, redundant descriptions are omitted.

In the electrostatic radiation device 1A, radiation is applied by applying a predetermined voltage to the spinning nozzle 2 and / or the counter electrode 5 by the first high voltage power supply 7 and / or the third high voltage power supply 11. A potential difference is generated between the nozzle 2 and the counter electrode 5, and the fibers are sucked electrically to fly toward the counter electrode 5 (above, the spinning step 1). The ionizing radiation 10a is irradiated onto this flying fiber to ionize the gas and act as an ion source. As a result, the charging of the fiber is neutralized, the emergency force is lost by the electrostatic force, and the fiber is recovered from the fiber recovery container 3 by the drop along the gravity or by the breeze. Therefore, it is possible to obtain an inorganic fiber aggregate having a low density with a low density (above, the integration step (2)). When the ionizing radiation source 10 is used, the dose can be adjusted independently of the formation of the potential difference between the spinning nozzle 2 and the counter electrode 5, so that the inorganic fiber assembly can be stably obtained. Do.

In addition, various radiation sources may be used as the ionizing radiation source 10, and an X-ray irradiation apparatus is particularly preferable. In addition, the counter electrode 5 should just have a potential difference generate | occur | produced with the spinning nozzle 2, and may be grounded, or the voltage may be applied. In addition, the ionizing radiation source 10 only needs to be able to irradiate a radiation with respect to a fiber, and does not need to be located behind the counter electrode 5. Furthermore, the counter electrode 5 does not have to be in the form of a net, and various members may be used as long as it can transmit ionizing radiation, and a vapor deposition film may be used.

FIG. 6: is explanatory drawing which showed typically another embodiment of the electrostatic spinning apparatus which can perform the spinning process (1) and the integration process (2) in the manufacturing method of this invention.

In FIG. 6, in the electrostatic spinning device 1B, the first spinning nozzle 2a and the second spinning nozzle 2b are disposed to face each other. A first sol solution supply 6a for supplying the inorganic sol solution for spinning and a first high voltage power supply 7 for applying a high voltage are connected to the first spinning nozzle 2a, and to the second spinning nozzle 2b, The second sol solution supply 6b for supplying the inorganic sol solution for spinning and the second high voltage power supply 8 for applying a high voltage of opposite polarity to the first high voltage power supply 7 are respectively connected. Otherwise, since it is the same structure as the electrostatic radiating apparatus 1, the overlapping description is abbreviate | omitted.

In the electrostatic spinning device 1B, voltages of opposite polarities are applied to the first spinning nozzle 2a and the second spinning nozzle 2b by the first high voltage power supply 7 and the second high voltage power supply 8, respectively. While discharging, the inorganic sol solution for spinning is discharged from the first spinning nozzle 2a and the second spinning nozzle 2b (above, the spinning step (1)). Then, the fibers charged with opposite polarities are contacted and approached by being discharged opposite to each other to neutralize the charges, and lose the emergency force by the electrostatic force, so that the fibers are dropped along the gravity or the fibers are blown out of the fiber recovery container 3 by the breeze. It is recovered. Therefore, it is possible to obtain an inorganic fiber aggregate having a low density with a low density (above, the integration step (2)). Further, by adjusting so that the sol solution discharge conditions from the first spinning nozzle 2a and the sol solution discharge conditions from the second spinning nozzle 2b are different from each other, the fiber diameters are different from each other, or the composition of the fiber constituent materials is different from each other. Inorganic fiber aggregates in which different kinds of inorganic fibers are mixed can be produced.

In addition, the discharge of the inorganic sol solution for spinning from the first spinning nozzle 2a and the second spinning nozzle 2b can be performed continuously or discontinuously. In addition, an electric field may be generated between the first spinning nozzle 2a and the second spinning nozzle 2b, and a high voltage may be applied to only one of these sides and the other side may be grounded. In addition, the 1st spinning nozzle 2a and the 2nd spinning nozzle 2b may or may not be heated.

In the above-mentioned electrostatic radiating apparatus 1, electrostatic radiating apparatus 1A, and electrostatic radiating apparatus 1B, it is embodiment which used one spinning nozzle with respect to one spinning nozzle 2, 2a, 2b. It does not need to be one, and in order to improve productivity, it may be provided with two or more spinning nozzles.

In addition, in these electrostatic spinning devices, the suction device 9 is provided below the collecting member 4 so that the speed of air in the spinning space can be 5 to 100 cm / sec, preferably 10 to 50 cm / sec. In addition to this, in addition to or instead of the suction device 9, a blower can be provided above the collecting member 4. Thereby, the collection property of a fiber can be improved and an inorganic type fiber assembly can be manufactured stably.

The inorganic fiber aggregate obtained in the integration step (2) can be subjected to the following adhesion step (3) to the inorganic fiber aggregate as it is integrated, or after the heat treatment, the following adhesion step (3) is performed. You can also By carrying out this heat treatment (hereinafter, it may be referred to as post-integration heat treatment when it is necessary to distinguish it from the adhesive heat treatment described later), the structure and the heat resistance of the inorganic fiber aggregate are stabilized.

In addition, heat processing can be performed using an oven, a sintering furnace, etc., The temperature is suitably set according to the inorganic component which comprises an inorganic fiber assembly.

It is preferable that this heat processing temperature after integration is 200 degreeC or more, and it is preferable that it is 300 degreeC or more. When the heat treatment is performed at such a temperature, the structure of the inorganic fiber aggregates is stabilized and the strength is increased, that is, the fibers are bonded to each other in the form of dots at their intersections. I can keep it.

On the other hand, the hydrophilicity of an inorganic fiber structure can be improved as this post-aggregation heat processing temperature is 500 degrees C or less. Moreover, when using as a culture base material, it is easy to culture a cell in a spheroid form. For example, when the inorganic fiber has a hydroxyl group, the amount of hydroxyl groups per fiber weight can be 50 μmol / g or more by performing heat treatment after integration at a temperature of 500 ° C. or lower, thereby improving hydrophilicity.

From another point of view, by increasing the post-aggregation heat treatment temperature higher than 500 ° C., the hydrophobicity can be increased, and the adhesion of cells can be enhanced. When used as a culture substrate, the cells can be easily cultured in sheet form, Since the adhesive force of inorganic fibers increases, the strength of the inorganic fiber structure can be increased.

In the bonding process (3), the inorganic sol solution for adhesion | attachment containing the compound which mainly uses an inorganic component mainly is provided to the whole including the inside of the inorganic fiber aggregate obtained by the process until now, and the excess inorganic sol solution for adhesion | attachment is carried out. After removing the mixture by aeration to form an inorganic sol solution-containing inorganic fiber aggregate (hereinafter, the first half of the bonding step (3) may be referred to as an inorganic sol solution imparting step). Heat treating (or naturally drying at room temperature) the inorganic inorganic sol solution-containing inorganic sol solution, and forming an inorganic fiber structure bonded with an inorganic adhesive in the whole including the inside (hereinafter, the bonding step (3 This latter half step of) can be referred to as a heat treatment step for bonding). In addition, when it is necessary to distinguish it from the post-integration heat treatment mentioned above, the said heat processing in the adhesive heat treatment process can be called adhesive heat treatment. The raw material (compound) constituting the adhesive inorganic sol solution is the same as the compound containing the elements constituting the inorganic fiber, but may be the same as or different from the spinning inorganic sol solution as long as it penetrates into the inorganic fiber aggregate. For example, it does not need to be ordinary, and may not be ordinary. In addition, particles may be included. The spinning inorganic sol solution may be diluted, and the concentration may be appropriately selected. In particular, it is preferable that it is a metal alkoxide hydrolysis-condensate. Furthermore, the said inorganic sol solution for adhesion | attachment may contain the metal ion containing compound demonstrated in detail in the metal ion containing compound containing solution provision process (4), and may not contain it.

The provision of the inorganic sol solution for adhesion to the inorganic fiber aggregate may be applied to the entirety of the inorganic sol solution uniformly, that is, in the same manner as the outer portion of the inorganic fiber aggregate, until the inorganic sol solution for adhesion can be sufficiently provided to the inside. Although it does not specifically limit, For example, it can implement by immersing an inorganic fiber aggregate in the adhesive inorganic sol solution. In the integration step (2), when the post-integration heat treatment of the inorganic fiber aggregate is carried out, the immersion treatment does not disperse well.

The excess adhesive inorganic sol solution contained in the inorganic fiber aggregate after immersion is removed by ventilation. Since the inorganic fiber aggregate is composed of inorganic fibers, the inorganic sol for bonding does not form a film between the whole fibers including the inside without deforming the thickness even if it is aerated by suction and / or pressure. The inorganic sol solution containing inorganic fiber aggregate which provided the solution can be obtained.

In the adhesive heat treatment step, the inorganic inorganic sol solution-containing inorganic fiber aggregate obtained in the inorganic sol solution applying step for drying is dried, and in the whole including the inside, the adhesive is bonded with an inorganic adhesive without forming a film between the inorganic fibers. One inorganic fiber structure can be produced. The adhesive heat treatment may be carried out by volatilizing a solvent or the like contained in the adhesive inorganic sol solution, and is not particularly limited. For example, the adhesive heat treatment may be performed by holding at a temperature of 80 to 150 ° C. for 10 to 30 minutes. Moreover, it can also dry naturally at room temperature. The "heat treatment for adhesion" in the present specification includes the following firing treatments in addition to the drying by heating and natural drying at room temperature.

In the bonding step (3), after the adhesive heat treatment for volatilizing the solvent or the like, if desired, in order to inorganicize the inorganic inorganic sol solution and / or the inorganic fiber included in the inorganic inorganic sol solution-containing inorganic fiber aggregate, A firing process can be performed. By performing this baking process, the intensity | strength and heat resistance of the inorganic adhesive agent which adhered the fiber intersection of an inorganic fiber assembly are improved. In addition, the strength and heat resistance of the inorganic fibers are improved. A baking process can be performed using a sintering furnace, for example, and the temperature is suitably set according to the inorganic component which comprises an inorganic adhesive agent and inorganic fiber. Generally, it is preferable that baking temperature is 200 degreeC or more, More preferably, it is 300 degreeC or more. Moreover, when manufacturing the inorganic fiber structure which has the functionality which provided the apatite, it is preferable to carry out at the baking temperature mentioned later. In addition, in the manufacturing method of this invention, this baking process may not be performed.

When bonding with an inorganic adhesive, it is preferable to carry out baking with no weight, so that a film may not be formed between inorganic fibers and a porosity will not be lowered.

Moreover, the hydrophilicity of an inorganic fiber structure can be improved as this adhesive heat processing temperature is 500 degrees C or less. Moreover, when using as a culture base material, it is easy to culture a cell in a spheroid form. For example, when an inorganic fiber has a hydroxyl group, since the amount of hydroxyl groups per fiber weight can be 50 micromol / g or more by performing the adhesive heat processing at the temperature of 500 degrees C or less, hydrophilicity improves.

In other respects, by increasing the adhesion heat treatment temperature higher than 500 ° C., the hydrophobicity can be increased, and the adhesion of cells can be enhanced. When used as a culture substrate, the cells can be cultured in the form of a sheet. Since the adhesive force of fibers increases, the strength and heat resistance of the inorganic fiber structure can be improved. Such bonding heat treatment can be performed using an oven, a sintering furnace, or the like, for example.

In the metal ion-containing compound-containing solution applying step (4), an inorganic fiber structure having functionality can be formed by applying a metal ion-containing compound-containing solution to the inorganic fiber structure.

As a metal which comprises a metal ion containing compound, calcium, sodium, iron, magnesium, potassium, copper, iodine, selenium, chromium, zinc, molybdenum, etc. are mentioned, for example. These metals have a cell function inducing factor or antibacterial action.

The metal ion containing compound may be, for example, a metal salt. Examples of the metal salts include chlorides, sulfates, phosphates, carbonates, hydrogen phosphates, hydrogen carbonates, nitrates, hydroxides, and the like. In particular, the inorganic fiber structure which has the function which provided calcium ion containing salt, magnesium ion containing salt, and apatite (apatite) can perform cell culture which improved cellular function.

As a provision method of a metal ion containing compound, the method of immersing an inorganic fiber structure in the metal ion containing compound containing solution, the method of apply | coating or spraying a metal ion containing compound containing solution to an inorganic fiber structure, etc. are mentioned, for example. . In the case where the inorganic fiber is a silica fiber, it is preferable that the metal ion-containing compound is immersed, coated or sprayed, followed by heat treatment (firing) to give the metal ion-containing compound at a high concentration.

More specifically, the inorganic fiber structure having the functionality to which the calcium ion-containing salt or the magnesium ion-containing salt is imparted is, for example, an inorganic type in a solution in which calcium salt or magnesium salt is dissolved in a suitable solvent (for example, lower alcohol). It can obtain by immersing a fiber structure or apply | coating or spraying the said solution.

In addition, the inorganic fiber structure having the functionality to which apatite is imparted is, for example, an inorganic fiber by immersing an inorganic fiber (especially a silica fiber) containing a hydroxyl group on the surface in an artificial body fluid containing at least phosphate ions and calcium ions. Apatite can be precipitated on the phase. In the case where the inorganic fiber is a silica fiber (particularly, a fibrous structure for bone culture substrate), the post-integration heat treatment may be performed in the integration step (2), or may be left as it is. When performing, it is preferable to heat-process an inorganic fiber assembly at the temperature of 500 degrees C or less, and it is more preferable that it is 120-300 degreeC. In this way, even if the post-integration heat treatment is not performed or the post-integration heat treatment is performed, the amount of hydroxyl groups per fiber weight can be 50 µmol / g or more, and preferably 100 µmol / g or more. .

Further, after applying the inorganic sol solution for bonding, in the bonding step (3), the adhesive heat treatment (drying and / or firing) is carried out at the same temperature range, and the amount of hydroxyl groups per fiber unit weight is 50 μmol / g or more (more preferably Is 100 µmol / g or more).

Inorganic fiber structure of the present invention, the inorganic fiber aggregates produced by the electrospinning method, the inorganic fiber aggregate produced by the step of irradiating and integrating the ions of the opposite polarity to the inorganic fiber, and aggregated to the whole including the inside. In the inorganic fiber structure bonded with an inorganic adhesive, a metal ion-containing compound is added if desired. The inorganic fiber structure of this invention can be produced by the manufacturing method of this invention, for example.

Inorganic fibers in the present invention include, for example, inorganic gel fibers, inorganic dry gel fibers or inorganic sintered fibers.

An inorganic gel fiber is a fiber in a state containing a solvent. For example, when the raw material of the inorganic fiber consists of tetraethoxysilane (TEOS), ethanol, water, and hydrochloric acid, the substance having the highest breaking point is water. , Fibers that have been heat treated at a temperature of less than 100 ° C. or not.

In addition, an inorganic dry gel fiber means the state in which the solvent etc. which were contained in a gel fiber were missing. For example, when the raw material of an inorganic fiber consists of tetraethoxysilane (TEOS), ethanol, water, and hydrochloric acid, since the substance with the highest breaking point is water, it is a fiber heat-processed at the temperature of 100 degreeC or more.

In addition, an inorganic type sintered fiber means the state in which the inorganic dry gel type fiber (porous) was sintered (porous). For example, when the raw material of an inorganic fiber is a silica type, it is a fiber heat-processed at 800 degreeC or more.

In the inorganic fiber structure of this invention, the average fiber diameter of an inorganic nanofiber is 3 micrometers or less so that surface area is large and it is excellent in functionality. Preferably it is 2 micrometers or less, More preferably, it is 1 micrometer or less.

"Average fiber diameter" means the arithmetic mean value of the fiber diameter in 50 points | pieces, and a "fiber diameter" means the thickness of the fiber measured based on the 5000 times the electron microscope photograph which imaged the inorganic fiber structure.

The inorganic fiber structure has a two-dimensional shape such as a nonwoven fabric, a hollow cylindrical shape, and a three-dimensional shape such as a cylindrical shape. In addition, the inorganic fiber structure of the three-dimensional shape can be produced by, for example, molding an inorganic fiber aggregate of a two-dimensional shape such as a nonwoven fabric.

Since the inorganic fiber structure of this invention has a high porosity (bulky) of 90% or more of porosity, and since fiber density is low, the inside of an inorganic fiber structure can be utilized effectively. For example, when used as a culture substrate, since the fiber density is low, the cell is easily spread to the inside of the culture carrier. Preferable porosity is 91% or more, More preferably, it is 92% or more, More preferably, it is 93% or more, More preferably, it is 94% or more. Although an upper limit is not specifically limited, It is preferable that it is 99.9% or less so that form stability is excellent.

In addition, a porosity can be computed from following Formula.

P = [1-Wf / (V × SG)] × 100

Where P is porosity (%), Wf is fiber weight (g), V is volume (cm ³ ), and SG is specific gravity (g / cm ³ ) of the fiber, respectively.

For example, when thickness is uniform like a nonwoven fabric, it can calculate from following Formula.

P = {1-Wn / (t × SG)} × 100

Here, P is the porosity (%), Wn is the basis weight (目 付, g / m ² ), t is the thickness (μm), SG is the specific gravity (g / cm ³ ) of the fiber, respectively.

In addition, basis weight is the value which measured the area and weight of the surface with the largest area, and converted into the weight per 1m <^2> , and thickness is the micro | micron set so that the load in the surface with the largest area may be 100 g / cm <^2>. Measured by the metric system.

In the case where the inorganic fiber structure is a two-dimensional form (especially a nonwoven fabric), it is preferable that the tensile strength at break is 0.2 MPa or more so as to have excellent shape retention and have sufficient strength. More preferably, it is 0.3 Mpa or more, More preferably, it is 0.4 Mpa or more, More preferably, it is 0.5 Mpa or more, More preferably, it is 0.55 Mpa or more.

This tensile breaking strength is the quotient of the cut load divided by the cross-sectional area of the inorganic fiber structure. In addition, a cutting load is the value measured on condition of the following, and a cross-sectional area is a value obtained from the product of the width and thickness of the test piece at the time of a measurement.

Product Name: Small Tensile Testing Machine

Model: TSM-01-cre Search Co., Ltd.

Test size: 5mm width × 40mm length

Chuck spacing: 20 mm

Tensile Speed: 20mm / min.

Initial load: 50 mg / 1d

The amount of hydroxyl groups per unit weight of fiber is preferably 50 μmol / g or more, more preferably 100 μmol / g or more, even more preferably 200 μmol / g or more, even more preferably 300 μmol / g or more, 400 μmol / g so as to have excellent hydrophilicity. It is more preferable that it is more than, and it is more preferable that it is 500 micromol / g or more.

The amount of hydroxyl groups per unit weight of the fiber is the portion obtained by dividing the amount of hydroxyl groups of the inorganic fiber structure by the amount of fibers (unit: g) of the inorganic fiber structure used for measuring the amount of hydroxyl groups.

In addition, the amount of hydroxyl groups is the value quantified using the neutralization titration method. That is, after dispersing the inorganic fiber structure in 50 mL of 20 vol% sodium chloride aqueous solution, 0.1 N sodium hydroxide aqueous solution is added dropwise to the neutralization point, and the amount of hydroxyl groups of the inorganic fiber structure is determined from the sodium hydroxide dropping amount necessary for neutralization ( See bibliography).

(references)

George W S., Determination of Specific Sufface Area of Colloidal Silica by Titration with Sodium Hydroxide, Anal. Chem .; 28,1981-1983, (1956)

Since the inorganic fiber structure of this invention is adhere | attached with an inorganic adhesive agent without forming a film between inorganic fiber in the whole including the inside, it is possible to maintain 90% or more of porosity. For example, when used as a culture carrier, it is possible to improve the supply efficiency of nutrients, oxygen and the like which are indispensable to the cells, and since there are many scaffolds required for cell culture, high density culture can be achieved.

The inorganic fiber structure which has the functionality of this invention gives a metal ion containing compound to the inorganic fiber structure of 90% or more of porosity as mentioned above.

As a metal which comprises a metal ion containing compound, calcium, sodium, iron, magnesium, potassium, copper, iodine, selenium, chromium, zinc, molybdenum, etc. are mentioned, for example. These metals have a cell function inducing factor or antibacterial action.

The metal ion containing compound may be, for example, a metal salt. Examples of the metal salts include chlorides, sulfates, phosphates, carbonates, hydrogen phosphates, hydrogen carbonates, nitrates and hydroxides. In particular, the inorganic fiber structure which has the function which provided calcium ion containing salt, magnesium ion containing salt, and apatite (apatite) can perform cell culture which improved cellular function.

<Examples>

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, these do not limit the scope of the present invention.

<< Fabrication and evaluation of non-machined fiber structure (nonwoven fabric) >>

(1) Fabrication of silica fiber nonwovens

In the present Example, 16 types of silica fiber nonwoven fabrics (Examples 1-9, Comparative Examples 1-7) of Table 1 were produced, and the evaluation was performed.

Spinning process (1) and Integrated process (2)

Tetraethoxysilane as a metal compound, ethanol as a solvent, water for hydrolysis, and hydrochloric acid as a catalyst are mixed at a molar ratio of 1: 5: 2: 0.003 and refluxed at a temperature of 78 ° C. for 10 hours. ), The solvent was then removed by a rotary evaporator and concentrated, and then heated to a temperature of 60 ° C to form a sol solution having a viscosity of 2 poise. The obtained sol solution was used as a spinning liquid (spun inorganic sol solution), and the gel silica fiber web was produced by the flat spinning method (comparative examples 6 and 7) which are neutral spinning (except Comparative Examples 6 and 7) or electrostatic spinning.

In addition, the said neutralization spinning method was implemented on the same spinning conditions as Example 8 of Unexamined-Japanese-Patent No. 2005-264374. That is, the counter electrode (the surface discharge element 25) of FIG. 4 was used as the counter electrode 5 of FIG. The details are shown below.

Spinning nozzle: 0.4 mm inner metal needle (cutting edge)

Distance between spinning nozzle and counter electrode: 200 mm

Counter electrode and ion generating electrode (also serving as positive electrode): Alumina film (dielectric substrate) having a thickness of 1 mm is sprayed on a stainless steel plate (organic electrode), and a tungsten wire having a diameter of 30 μm (discharge electrode thereon) ) And the surface of the creepage discharge element (equipped with a tungsten wire surface facing the radiation nozzle, grounded and applied 50 Hz AC high voltage between the stainless steel plate and the tungsten wire by AC high voltage power supply)

First High Voltage Supply: -16 kV

2nd high voltage power supply: ± 5kV (peak voltage of alternating surface: 5kV, 50Hz)

Airflow: 25 cm / sec in the horizontal direction, 15 cm / sec in the vertical direction

Atmosphere in the radiation chamber: temperature 25 ℃, humidity 40% RH or less

Continuous spinning time: 30 minutes or more

In addition, the said flat plate spinning method was implemented in the following procedures. As a spinning apparatus, the apparatus of FIG. 1 of Unexamined-Japanese-Patent No. 2005-194675 was used. The spinning liquid is supplied to a stainless steel nozzle having an internal diameter of 0.4 mm at a pump rate of 1 g / hour, and the spinning liquid is discharged from the nozzle into a spinning space (temperature 26 ° C., relative humidity 40% or less), and the nozzle A voltage (-16 kV) was applied to the ground, and a stainless steel non-porous roll (distance from the nozzle: 10 cm) was grounded, and then made thinner by applying an electric field to the spinning liquid. Fibers were formed, integrated onto a rotating non-porous roll, and a gel silica fiber web was formed.

After accumulation  Heat Treatment Process (3)

Next, except for Example 7 and Comparative Example 1, the gel silica fiber web obtained in the above step was subjected to the heat treatment temperature (120 ° C, 300 ° C, 500 ° C, or 800 ° C) described in the step (3) of Table 1 below. The silica fiber web (basic weight: 10 g / m <^2> ) was produced by heat processing after integration.

Adhesive Inorganic  Sol solution imparting process (4)

As an inorganic sol solution for adhesion used for inter-fiber adhesion, tetraethoxysilane as a metal compound, ethanol as a solvent, water for hydrolysis, and nitric acid as a catalyst are mixed in a molar ratio of 1: 7.2: 7: 0.0039. The reaction was carried out at 25 ° C for 25 hours and at 300 rpm under stirring conditions. After reaction, it diluted with ethanol so that solid content concentration of silicon oxide might be 0.25%, and it was set as the silica sol lean solution (adhesive inorganic sol solution).

In the silica fiber web obtained in the said process, about Example 1 thru | or Example 9 and Comparative Example 7, after immersing in the said silica sol lean solution, the excess silica sol lean solution is removed by suction [process of Table 1] (4) As method A] described in the column, a silica sol lean solution-containing silica fiber web was produced.

In addition, about the comparative example 1 thru | or the comparative example 3, and the comparative example 6, this process was not implemented. In Comparative Example 4, the silica sol lean solution-containing silica fiber web was sprayed by spraying the silica sol lean solution with the spray [method B described in the step (4) of Table 1] by spraying. Made. In this silica sol lean solution containing silica fiber web, the silica sol lean solution was provided only to the surface of a silica fiber web. About the comparative example 5, after immersing the silica fiber web obtained at the said process in the said silica sol lean solution, the excess silica sol lean solution was removed using two roll press machines [In the process (4) column of Table 1), As described method C], a silica sol lean solution-containing silica fiber web was produced.

Adhesive Heat Treatment Process (5)

For Examples 1 to 9 and Comparative Example 7, the silica sol lean solution-containing silica fiber web was held for 30 minutes in an atmosphere of 110 ° C. for drying removal of the solvent contained in the inorganic adhesive (silica sol lean solution). (1st heat processing process for bonding) was performed. On the other hand, about Comparative Examples 1-6, the adhesive 1st heat processing process was not performed.

Then, about Example 2, Example 3, Example 5, Example 6, Comparative Example 4, Comparative Example 5, and Comparative Example 7, the silica sol lean solution-containing silica fiber web obtained in the above step is A silica fiber nonwoven fabric was produced by bonding heat treatment (adhesive second heat treatment step) at the heat treatment temperature (200 ° C or 500 ° C) described in Step (5).

On the other hand, about Example 1, Example 4, Examples 7-9, Comparative Examples 1-3, and Comparative Example 6, the adhesive 2nd heat treatment process was not performed.

(2) Evaluation of Silica Fiber Nonwoven Fabric

About the 16 types of silica fiber nonwoven fabrics (Examples 1-9, Comparative Examples 1-7) produced by said (1), it cut | disconnected in size of 10 cm x 10 cm, and the result which performed various measurements was shown in Table 1. . In addition, also in any silica fiber nonwoven fabric, the average fiber diameter of the nanofiber which comprises it was 0.8 micrometer.

In addition, the thickness of a nonwoven fabric is the value measured by the micrometer method set to have a weight of 100 g / cm <^2> , and apparent density means the value which divided the basis weight (weight converted into the size of 1m <^2> ) by thickness, respectively. .

In addition, the conditions of the cutting load measurement were shown below.

Product Name: Small Tensile Testing Machine

Type: TSM-01-cre search

Test size: 5mm × 40mm

Chuck spacing: 20 mm

Tensile Speed: 20mm / min

Initial load: 50 mg / 1d

Porosity is the following formula:

[Porosity (%)] = [1- (basic weight / thickness / specific gravity)] × 100

(Unit = g / m ² of basis weight, unit = μm of thickness, specific gravity of silica = 2 g / cm ³ )

Calculated by

<< production of culture carrier >>

Comparative example  8

The gel silica fiber web obtained in Comparative Example 1 was used as a comparative culture carrier (hereinafter referred to as culture carrier a) used in the following evaluation test. The average fiber diameter of the nanofibers constituting the culture carrier was 0.8 μm.

Comparative example  9

The silica fiber web obtained in the said Comparative Example 3 was made into the comparative culture carrier (henceforth a culture carrier b) used for the following evaluation tests. The average fiber diameter of the nanofibers constituting the culture carrier was 0.8 μm.

Example  10

Tetraethoxysilane as a metal compound, ethanol as a solvent, water for hydrolysis, and nitric acid as a catalyst were mixed at a molar ratio of 1: 7.2: 7: 0.0039, and reacted for 15 hours at a temperature of 25 ° C. and a stirring condition of 300 rpm. Then, it diluted with ethanol so that solid content concentration of silicon oxide might be 0.5%, and set it as the silica sol lean solution (adhesive inorganic sol solution).

After immersing the silica fiber web obtained in the said Comparative Example 3 in the said silica sol lean solution, the excess sol solution was removed by suction, and the silica sol lean solution containing silica fiber web was prepared.

In order to dry-dry the solvent contained in a silica sol lean solution, the silica sol lean solution containing silica fiber web was hold | maintained for 30 minutes in 110 degreeC atmosphere (1st heat treatment process for adhesion | attachment).

Subsequently, this silica sol lean solution-containing silica fiber web was subjected to a second heat treatment for adhesion at a temperature of 500 ° C. to prepare a silica fiber nonwoven fabric (porosity: 93%, tensile strength at break: 0.572 MPa, and hydroxyl amount: 35 μmol / g). This silica fiber nonwoven fabric was used as a culture carrier (culture carrier A). The average fiber diameter of the nanofibers constituting the culture carrier was 0.8 μm.

Comparative example  10

What adjusted PVA (polymerization degree 1000, fully saponification type) to the density | concentration of 15 wt% was used as a spinning liquid.

As a spinning apparatus, the apparatus of FIG. 1 of Unexamined-Japanese-Patent No. 2005-194675 was used. The spinning solution prepared above is supplied to a stainless steel nozzle having an internal diameter of 0.4 mm at a rate of 0.5 g / hour by a pump, and the spinning solution is discharged from the nozzle into a spinning space (temperature 26 ° C., relative humidity 50%), Applying a voltage (24 kV) to the nozzle, grounding the stainless steel non-porous roll (distance with the nozzle: 10 cm), which is reduced in size by applying an electric field to the spinning liquid, forms a PVA fiber, and rotates on the non-porous roll. Was integrated into a PVA fiber web.

The insolubilization process was performed by heat-processing 150 degreeC and 30 minute (s) after integration to this PVA fiber web. The obtained PVA-electrostatic spinning nonwoven fabric (porosity: 83%) was used as a culture carrier (culture carrier c). The average fiber diameter of the nanofibers constituting the culture carrier was 0.2 µm.

<Evaluation of culture carrier>

(1) Evaluation using CHO-K1 derived from Chinese hamster ovary cells

CHO-K1 cells (ATCC: CCL-61, Reference: Puch TT, et al., Genetics of somatic mammalian cells ⅲ.Long-term cultivation of euploid cells from human and animal subjects., J. Exp. Med. 108: 945-956,4958.PudMed: 13598821) was cultured using DMEM (Dulbecco's Modified Eagle's Medium) with a medium added with 10% FBS, and antibiotics (60 μg / mL penicillin and 100 μg / mL streptomycin), 37 ° C., 5% CO ₂ It carried out under conditions.

In the culture environment, a culture carrier for evaluation (1 cm x 1 cm) was placed in each well of a 24-well plate, and 1 mL of CHO-K1 cells (5 x 10 ⁵ cells / mL) were seeded, and the medium was exchanged every day. Done.

SEM images showing the cell morphology of the 14th day of culture were cultured with respect to the culture carrier A of the present invention prepared in Example 10 and the comparative culture carriers a, b, and c prepared in Comparative Examples 8 to 10 (cultivation). In the carrier A) and FIG. 8 (culture carrier c), the cell adhesion rate on the first day of culture showing cell adhesion was shown in FIG. 9, and the number of cells per unit dish up to 14 days was shown in FIG. 10, respectively. In addition, the cell adhesion capacity,

(Cell number on the carrier / number of sowing cells) × 100

It evaluated by the cell adhesion rate computed by

In the culture carrier A of the present invention, as shown in Fig. 7, CHO-K1 cells adhered and expanded on the entire surface of the carrier, and proliferated, whereas in the comparative culture carrier c, the culture carrier c was spherical to the surface of the culture carrier. It was growing while forming a cell mass of.

Comparing the culture carrier A and the culture carriers a to c with respect to the cell adhesion ability, as shown in Fig. 9, the culture carrier A had the highest adhesion between the cells and the carrier, and the cells adhered well to the fibers. The cell morphology of the above-mentioned culture carrier c is one of the reasons that the interaction between the carrier and the cell is weak.

As shown in Fig. 10, in two weeks of culture, the culture carrier A of the present invention had a significantly improved cell proliferation ability than the culture carriers a to c. The culture carriers a to b were difficult to observe because the fibers were loosened in the culture solution after several days from the start of the culture and the expansion of the carrier was observed. In addition, the culture carrier c was excessively dense in structure, difficult to observe, and poor in operability.

The culture carriers a to b produced by the neutralizing spinning method have a sufficient surface area to be a scaffold for cells required for three-dimensional culture, but have poor adhesion between the fibers or poorly adhered to each other because of poorly adhered structures. Therefore, it is not possible to maintain a uniform space serving as a cell scaffold, and good cell proliferation is unlikely to occur. On the other hand, the culture carrier A has sufficient cell scaffolding necessary for cell proliferation and is adhered between fibers, so that the shape retention in the culture solution is good, and the porosity and uniform culture space of 90% or more can be maintained. Therefore, cell culture is possible at high density. Moreover, the supply efficiency of nutrients, oxygen, etc. which are indispensable to a cell can be improved, and favorable cell proliferation is possible.

Control of fiber density and thickness in the cell culture carrier of the present invention resulted in improvement of these cell proliferation capacities.

(2) Evaluation using human liver cancer derived cell line HepG2

Of HepG2 cells (ATCC: HB-0865, Reference: Knowles BB, et al., Human hepatocellular carcinoma cell lines secrete the major plasma proteins and hepatitis B surface antigen., Science 209: 497-499,1980. Pub Med: 6248960). The culture was added to Williams's Medium E (purchase company Sigma) by adding 10% fetal bovine serum (FBS), antibiotics (60 μg / mL penicillin and 100 μg / mL streptomycin), and 1 mmol / L NH ₄ Cl. Using medium, 37 ° C., 5% CO ₂ It carried out under conditions.

In a culture environment, an evaluation culture carrier (1 cm x 1 cm) was placed in each well of a 24-well plate, 1 mL of HepG2 cells (5 x 10 ⁵ cells / mL) were seeded, and medium exchange was performed every day. .

For the culture carrier A of the present invention prepared in Example 10, and the comparative culture carriers a, b, and c prepared in Comparative Examples 8 to 10, changes in the number of cells per unit dish up to 14 days are shown in FIG. 11 and 14 days. As a result of measuring the ammonia removal ability in the medium brought up to the cell, the change of albumin concentration of the cell up to 14 days was shown in FIG.

As shown in FIG. 11, when HepG2 was incubated for 14 days with the culture carrier A and the comparative culture carriers a to c of the present invention, the culture carrier A had a significantly improved cell proliferation ability than the culture carriers a to c. .

Comparing the ammonia removal ability, as shown in FIG. 12, the culture carriers a to c did not show high functionalization of cells during the two-week incubation period, and were in the direction of secreting ammonia on the contrary. However, the culture carrier of the present invention has improved cell function and improved detoxification ability (ammonia removal ability), which is one of the original functions of hepatocytes.

HepG2 cells secrete ammonia in monolayer culture (two-dimensional culture on a plate). However, when HepG2 cells are cultured in three dimensions in three dimensions, a function of absorbing and metabolizing ammonia occurs. Therefore, in the cell culture carrier for comparison, the effect of the three-dimensionalization of cells is not observed, but the culture carrier A of the present invention is cultured three-dimensionally, and is cultured in a state closer to the state of liver cells in vivo. have.

Even when the albumin concentration of HepG2 cells cultured in the culture carrier A was changed, as shown in FIG. 13, since the albumin concentration increased during the culture period, the HepG2 cells cultured in the culture carrier A were normally expanded.

(3) comprehensive evaluation

Table 2 shows the comprehensive evaluation based on the results of the above (1) and (2).

The cell proliferation ability in Table 2 was evaluated based on Comparative Example 10 (PVA). About cell adhesiveness, about 30% or less made "x", about 30%-50% "△", and made about 50% or more "o".

<< production of functional inorganic fiber structure >>

Tetraethoxysilane as a metal compound, ethanol as a solvent, water for hydrolysis, and hydrochloric acid as a catalyst are mixed in a molar ratio of 1: 5: 2: 0.003 and mixed at a temperature of 78 캜 for 10 hours. The reflux operation was carried out, and then the solvent was removed by a rotary evaporator, concentrated, and then heated to a temperature of 60 ° C. to form a sol solution having a viscosity of 2 poise. The obtained sol solution is used as a spinning solution (spun inorganic sol solution), and is spun by neutral spinning, that is, by electrospinning, and irradiated and integrated with ions of opposite polarity to form a gel fiber web (inorganic fiber aggregate). Formed).

In addition, the said neutralization spinning method was implemented on the same spinning conditions as Example 8 of Unexamined-Japanese-Patent No. 2005-264374. That is, the counter electrode (the surface discharge element 25) of FIG. 4 was used as the counter electrode 5 of FIG. The details are shown below.

Spinning nozzle: 0.4 mm inner metal needle (cutting edge)

Distance between the spinning nozzle and the counter electrode: 200 mm

Counter electrode and ion generating electrode (also serving as both electrodes): Alumina film (dielectric substrate) having a thickness of 1 mm is sprayed on a stainless steel plate (organic electrode), and a tungsten wire (discharge electrode) having a diameter of 30 μm is 10 mm thereon. Creeping-discharge elements at equal intervals of (Turn the tungsten wire surface against the radiating nozzle and ground, and apply AC high voltage of 50Hz by AC high voltage power supply between stainless steel plate and tungsten wire)

First High Voltage Supply: -16 kV

2nd high voltage power supply: ± 5kV (peak voltage of alternating surface: 5kV, 50Hz)

Airflow: 25 cm / sec in the horizontal direction, 15 cm / sec in the vertical direction

Atmosphere in the radiation chamber: temperature 25 ℃, humidity 40% RH or less

Continuous spinning time: 30 minutes or more

The obtained gel-like fiber web (inorganic fiber aggregate) is heat-treated after integration at a temperature of 800 ° C., 120 ° C., or 500 ° C. to form a calcined inorganic fiber aggregate (“Sample 1”, “Sample 2”, “Sample 3” in order). did.

Tetraethoxysilane as a metal compound, ethanol as a solvent, water for hydrolysis, and nitric acid as a catalyst were mixed at a molar ratio of 1: 7.2: 7: 0.0039, and reacted for 15 hours at a temperature of 25 ° C. and a stirring condition of 300 rpm. Then, it diluted with ethanol so that solid content concentration of silicon oxide might be 0.25%, and it was set as the silica sol lean solution (adhesive inorganic sol solution).

After immersing the said samples 1 to 3 in this bonding inorganic sol solution (solid content concentration: 0.25%), the excess silica sol lean solution is removed by suction, and it hold | maintains for 30 minutes in 110 degreeC atmosphere, The solvent of the sol-lean solution was removed, and the adhesion sample 1, the adhesion sample 2, and the adhesion sample 3 were formed, respectively (first heat treatment for adhesion).

Subsequently, Example 14 (porosity: 94.3%, tensile strength at break: 0.568 MPa, amount of hydroxyl groups: 37 µmol / g) was applied to the baked adhesive sample 1, in which the adhesive sample 1 was subjected to a second heat treatment (firing treatment) for adhesion at a temperature of 500 ° C. for 3 hours. ) In addition, the adhesive sample 2 was set as Example 15 (porosity: 93.5%, tensile strength at break: 0.292 MPa, amount of hydroxyl groups: 1500 micromol / g).

Further, the baked adhesive sample 3 (porosity: 94.2%, tensile breaking strength: 0.513 MPa, hydroxyl group amount: 54 μmol / g), which was baked for 3 hours at 500 ° C., was added to a calcium chloride ethanol solution (concentration: 0.1 N). After soaking for 3 hours, it baked at 500 degreeC for 3 hours, and also washed with water, and prepared the calcium-containing fiber structure 1, and was made into Example 11. When the element of the calcium-containing fiber structure 1 was analyzed by X-ray photoelectron analysis, the calcium element ratio was 14.36%. For reference, the calcium element ratio of the plastic adhesive sample 3 (standard product) was 0.51%.

Furthermore, after baking the adhesive sample 3 which baked the adhesive sample 3 at 500 degreeC for 3 hours in the magnesium chloride ethanol solution (concentration: 0.1N) for 3 hours, it baked at 500 degreeC for 3 hours, and further washed with water. To prepare a magnesium-containing fiber structure 2, to obtain Example 12. When the elements of the magnesium-containing fiber structure 2 were analyzed by X-ray photoelectron analysis, the magnesium element ratio was 22.54%. For reference, the magnesium element ratio of the plastic adhesive sample 3 (standard product) was 0.94%.

In addition, separately prepared artificial fluids (142.0 mmol / L Na ⁺ , 103.0 mmol / L Cl ⁻ , 10.0 mmol / L HCO ₃ ⁻ , 5.0 mmol / L K ⁺ , 1.5 mmol / L Mg ^{2 +} , 2.5 mmol / L of ^{Ca 2 +, 1.0mmol / L HPO} 4 2-, and SO ₄ ² of 0.5mmol / L for ^- during the same solution of high ionic concentration as a human body fluid comprising a), an adhesive sample 2 (hydroxyl groups: 1500μmol / g) was immersed for one week, the apatite was precipitated on the fiber surface, the apatite-containing fiber structure 3 was prepared, and it was set as Example 13.

<< Function Evaluation of Functional Inorganic Fiber Structures >>

In the following Examples 11 to 15, various functional evaluations as the culture carrier were performed. In addition, also in any fiber structure, the average fiber diameter of the nanofibers which comprise it was 0.8 micrometer.

Example 11 Calcium-Containing Fiber Structure 1

Example 12 Magnesium-Containing Fiber Structure 2

Example 13 Apatite-containing Fiber Structure 3

Example 14 Plastic Adhesion Sample 1

Example 15 Adhesive Sample 2

Human osteosarcoma Mg63 cells (IFO50108) were cultured on the fibrous structures or samples, respectively, and compared and examined for the ability to differentiate into adult bone. As the culture medium, 10% fetal bovine serum (FBS), antibiotics and 0.1% non-essential amino acid were added to MEM medium (Invitrogen). 1 mL of 2 * 10 <^5> cells / mL was seeded on a sample or a fiber structure, and culture evaluation was performed for 21 days.

The cell number trend is shown in FIG. In addition, the time course of the enzyme activity (unit: ABS / 10 ³ cells) per unit cell of alkaline phosphatase (ALP), an enzyme secreted when bone cells differentiate into bone, is shown in FIG. The value is shown in FIG. The stronger the activity of ALP, the easier the cells are to differentiate into bone. In addition, after ALP activity wash | cleans each fiber structure or a sample using the phosphate buffer, 100 microliters of 1% Triton X-100 containing phosphate buffers are added, shaken at 37 degreeC for 30 minutes, and also 0.006 g / mL p -100 microliters of nitrophenyl phosphate was added, shaken for 2 hours, and it determined by measuring the absorbance in the wavelength of 405 nm of a reaction liquid.

As shown in FIGS. 14-16, the fiber structure (Examples 14 and 15) of this invention which does not contain a metal ion containing compound is the calcium containing fiber structure 1 (Example 11) which is a preferable embodiment of this invention. Cells having superior cell proliferation ability but low cell function are cultured than the magnesium-containing fiber structure 2 (Example 12) and the apatite-containing fiber structure 3 (Example 13).

Comparing the ALP activity of each of the fibrous constructs on the 14th day of culture, the fibrous constructs of Examples 11 to 13 had higher ALP activity than those of Examples 14 or 15, and the lowest value of Example 12 and Example 12 There is a 1.5-fold difference in ALP activity, and cells are likely to induce differentiation into bone.

Therefore, the fibrous structure having functionality, which is a preferred embodiment of the present invention, is effective when cell culture with enhanced cell function is to be performed.

<< Reference example: Measurement of the amount of hydroxyl groups and evaluation of cell culture in inorganic fiber structures having different heat treatment temperatures.

(1) Fabrication of inorganic fiber structure and measurement of hydroxyl level

The gel-like silica fiber web obtained in Comparative Example 1 was heated to a temperature of 120 ° C., 200 ° C., 250 ° C., 300 ° C., 500 ° C. and 800 ° C. at a rate of 1 ° C./min. The amount of hydroxyl groups per fiber weight of the fiber when held for 3 hours and heat treated at each temperature was measured. In addition, also in any silica fiber nonwoven fabric or the gel silica fiber web before baking, the average fiber diameter of the nanofibers which comprise it was 0.8 micrometer.

The results are shown in FIG. In addition, in FIG. 17, considering the case where an inorganic fiber structure is used for a cell culture carrier, the fiber unit after heat-processing an inorganic fiber structure at 120 degreeC, after ethanol sterilization or autoclave sterilization is carried out. The amount of hydroxyl per weight is also listed.

From this FIG. 17, if the temperature is 500 ° C or less, the amount of hydroxyl groups per fiber unit weight can be 50 µmol / g or more. If the temperature is 300 ° C or less, the amount of hydroxyl groups per fiber unit weight can be 100 µmol / g or more. If it was 250 degrees C or less, the amount of hydroxyl groups per fiber weight may be 400 micromol / g or more, and if it was 200 degrees C or less, it turned out that the amount of hydroxyl groups per fiber weight may be 500 micromol / g or more.

It was also found that the amount of hydroxyl groups per unit weight of fiber after ethanol sterilization or after autoclave sterilization did not change from before sterilization.

(2) Preparation of culture carrier and cell culture evaluation

The gel-like silica fibrous web obtained in Comparative Example 1 was heated to a temperature of 100 ° C., 300 ° C., or 500 ° C. at a rate of 1 ° C./min., And held at that temperature for 3 hours. And a culture carrier were prepared.

Cell cultures of the human liver cancer-derived cell line HepG2 were carried out for 14 days according to the culture conditions described above using each of these culture carriers (as a control, gel silica fiber web before firing).

SEM photographs taken after 14 days of incubation were shown in Fig. 18 (Reference Example 1: Unbaked), Fig. 19 (Reference Example 2: Firing at 100 ° C), and Fig. 20 (Reference Example 3: 300 ° C). Firing) and FIG. 21 (Reference Example 4: firing at 500 ° C).

From the results shown in Figs. 18 to 21, the amount of hydroxyl groups in the culture carrier is high and the hydrophilicity is high, so that it is easy to culture the spheroid cells, the amount of hydroxyl groups in the culture carrier is low, and the hydrophobicity is high. It can be seen that it is easy to culture the cells of the form.

The inorganic fiber structure of the present invention can be applied to, for example, a culture carrier such as a heat insulating material, a filter medium, an analysis tool, a cell, a catalyst carrier, an antibacterial material and the like. In addition, the cell culture carrier can be applied to all fields using cell culture. For example, analytical tools using cell culture, regenerative medicine, useful substance production, etc. are mentioned.

As mentioned above, although this invention was demonstrated according to specific embodiment, the deformation | transformation and improvement obvious to those skilled in the art are included in the scope of the present invention.

Claims (14)

An inorganic fiber structure composed of inorganic nanofibers having an average fiber diameter of 3 μm or less, wherein an inorganic fiber structure having a porosity of 90% or more in which the whole including the inside is bonded with an inorganic adhesive. The inorganic fiber structure according to claim 1, wherein the tensile breaking strength is 0.2 MPa or more. The inorganic fiber structure according to claim 1 or 2, wherein the amount of hydroxyl groups per fiber weight of the fiber is 50 µmol / g or more. The inorganic fiber aggregate according to any one of claims 1 to 3, wherein the inorganic fiber spun by the electrospinning method includes an inside of the inorganic fiber aggregate produced by irradiating and integrating ions of opposite polarity to the inorganic fiber. Inorganic fiber structure WHEREIN: It adhere | attaches with the inorganic adhesive agent. The inorganic fiber structure according to any one of claims 1 to 4, wherein no coating is formed between the inorganic fibers. The inorganic fiber structure which has functionality which provided the metal ion containing compound to the inorganic fiber structure of any one of Claims 1-5. The inorganic fiber structure according to any one of claims 1 to 6, which is used as a culture carrier. (i) spinning an inorganic fiber by an electrospinning method from a spinning inorganic sol solution containing a compound mainly composed of an inorganic component,
(Ii) irradiating and integrating ions of opposite polarity to the inorganic fibers to form an inorganic fiber aggregate, and
(Iii) Applying the inorganic sol solution for adhesion containing the compound mainly composed of an inorganic component to the whole including the inside of the said inorganic fiber aggregate, removing the excess inorganic sol solution for adhesion by aeration, and removing the inside Forming the inorganic fiber structure bonded with the inorganic adhesive in the whole containing,
Method for producing an inorganic fiber structure comprising a. The manufacturing method of the inorganic fiber structure of Claim 8 which heat-processes after forming an inorganic fiber aggregate in the process of forming (ii) an inorganic fiber aggregate. The manufacturing method of the inorganic fiber structure of Claim 9 whose heat processing temperature is 500 degrees C or less. The method for producing an inorganic fiber structure according to any one of claims 8 to 10, wherein in the step of forming the inorganic fiber structure, the excess adhesive inorganic sol solution is removed by aeration, followed by heat treatment. The manufacturing method of the inorganic fiber structure of Claim 11 whose heat processing temperature is 500 degrees C or less. The method for producing an inorganic fiber structure according to any one of claims 8 to 12, wherein the spinning inorganic sol solution and / or the bonding inorganic sol solution contains a metal ion-containing compound. The method for producing an inorganic fiber structure according to any one of claims 8 to 13, wherein after the step of forming the inorganic fiber structure, a solution containing a metal ion-containing compound is added to the inorganic fiber structure.

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